Process of extracting precious metals from their ores.



No. 664,060. 4 Patented Dec. l 8, I900.

' J P. SCHUCH", 1R.

PROCESS, OF EXTBACTING .PREGIOUSJVIETALS FROM THEIR URES. (Applicationfl 1ed Decv27, 1898.)

(No Model.)

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UNITED STATES PATENT FFICE.

JOHN PHILIP SOHUOH, JR., OF ORIPPLE GREEK, COLORADO.

PROCESS OF EXTRACTING PRECIOUS METALS FROM THElR ORES.

SPECIFICATION forming part of Letters Patent No. 664,060, dated December18, 1900.

Application filed December 27, 1898. Serial No. 700,405. (No specimens.)

To all whom it may concern.-

Be it known that 1, JOHN PHILIP SoHUcH, Jr., a citizen of the UnitedStates, residing at Cripple Creek, in the county of El Paso and State ofColorado, have invented a new and useful Process of Extracting PreciousMetals from Their Ores, of which the following is a specification.

This invention relates to an improved process of extracting preciousmetals from their ores; and it has for one object to provide fortreating metal-bearing ores by the use of oyanogen containing solventsin a novel and efficient manner, whereby a much larger percentage of thevalue of the ores may be saved than has been heretofore possible by theordinary cyanid process.

Heretofore in treating gold-bearing ores by the common cyanid processthe ore is first crushed, dried, and rolled to a proper degree offineness, and that which requires roasting is then conveyed to theroasters, while the oxidized ore, which does not require roasting, isdelivered to the bin or receptacle therefor. After the portion of theore to be roasted has passed through this step of the process the sameis conveyed to the cooling-room before being deposited in the bin orreceptacle referred to, which contains the ore requiring no roasting.All of the ore is then removed by manual labor into the ordinarystationary cyahid-tanks, and after these tanks are filled with the orethe cyanid solution is introduced therein. In this process the filledcyanid-tanks,with the solution and ore therein, are permitted to remainfilledand unmolested for a suflicient length of time for the solution toact on the ore, after which the gold-bearing solution is drawn off andallowed to flow to the precipitation-room, while the tailings in thetank are then washed with water and shoveled out, or sluiced out whenthis is possible. In carrying out this old cyanid process the percentageextracted rarely exceeds ninety per cent. of the ore value, whereas thepresent invention provides a process for saving a larger per cent. ofthe ore value, while at the same time permitting of the mixing togetherof various grades of ore with a cyanid solution, so as to make one evengrade out of ores of various values.

A further object of the invention is to provide a process which involvesthe thorough aeration of the ore and solution during mixing, whereby theoxygen of the air may be utilized to assist in dissolving the gold inthe ore.

The process contemplated by the present invention may be carried out byany practical means which would involve the mixing of the cyanidsolution with the ore prior to its introduction into thelixiviation-tanks, as this is one of the leading objects of theinvention namely, to overcome the objection to first mixing the ore withthe cyanid solution directly in such tanks. However, the preferredmanner of carrying out the process is in connection with the improvedmixing-machine disclosed in my contemporaneously-pending application,Serial No. 697,780.

The preferred form of mixing machine or apparatus with which the processis carried out is shown in the accompanying drawing, in which the figureis a sectional view thereof.

The mixing-machine illustrated in the drawing essentially consists of anupright tank 1 of the required capacity, which is entirely open at theupper end thereof and has connected with the bottom a solutiondrainagepipe 9, which leads to the usual precipitationboxes in theprecipitation-room, whereby the gold-bearing solution which percolatesto the main bottom of the tank may be conveyed to the precipitation-roomto provide for precipitating the precious metal from the solution.

The said tank 1 has fitted within the bottom thereof a strainer 10,through which the goldbearing solution must pass before reaching thedrainage-pipe 9, and serves to collect and retain sand, slime, and otherimpurities contained in the ore-or evolved by the chemical action of thecyanid solution thereon. The said strainer 10 therefore effects aseparation between the gold-bearing solution and the ore pulp or slushwhich is mixed with more or less of the solution, as the result of themixing operation within the mixing-tank, and to provide for carrying offsaid ore pulp or slush which does not penetrate the strainer the tank 1has fitted thereto above the plane of the strainer an ore-dischargespout 16, through which the ore pulp or slush, which is necessarilysaturated with more or less of the cyanid solution, passes and isdelivered into the lixiviation-tanks.

To provide for an intimate mixing of the ore and cyanid solution withinthe mixingtank, the latter has arranged therein a revoluble agitator 18,and a solution-supply pipe 40 is fitted in one side of the tank near thetop thereof to provide fordelivering into the same a constant stream ofthe cyanid solution.

Other details of the mixing-machine which are not essential to thepresent invention are fully described in the other application hereinreferred to.

Now in the ordinary process of treating gold-bearing ores, as explainedin the statement of invention, the oxidized ore which has been crushedand reduced to a propel-degree of fineness does not need roasting, whileother portions of the ore must be subjected to the roasting step. In thepresent invention, however, instead of allowing the roasted ore tobecome entirely cold in the cooling-room the same is conveyed ordelivered by a conveyer or any suitable means through a feed-chute 38directly into the open upper end of the mixing-tank 1 while the ore isstill in a warm condition. At the same time a stream of the oxidized oreis delivered from this receptacle by any suitable means, preferablythrough a feed-chute 39, into the open upper end of the mixing-tank.While the separate portions of the ore are thus being delivered into themixing-tank a constant stream of the cyanid solution is also beingdelivered into the tank by the solution-supply pipe 40, previouslyreferred to, and as the agitator 18 is constantly revolved in the tankthe entire mass of ore is intimately mixed with the solution, therebyinsuring an even and uniform extraction of the precious metals fromtheir ores. As previously explained, the gold-bearing cyanid solutionpasses through the strainer in the bottom of the tank and into thesolution-drainage pipe 9, through which it is carried to theprecipitation-room, while the ore slush or pulp, mixed with thesolution, discharges through the spout 16 and is delivered to thelixiviation-tanks. the ore is thoroughly mixed with the cyanid solutionprior to its introduction into the lixiviation-tanks.

In carrying out the invention it is necessary that the ore and cyanidsolution while being mixed together must be thoroughly aerated orcharged with air, so that the oxygen from the air will assist indissolving the gold in the ore. By using the cyanid solution instead ofwater on the ore at the stampmills it is unnecessary to charge themixture within the mixing-tank with air. In fact, the free-gold ores oroxidized ores can be treated through the stamp-mill by using the cyanidsolution instead of water, and the solution, carrying the fine ore withit, may be either run over amalgainating-plates directly to thecyanid-tanks or to the mixing-tank, herein described; but in eitherevent it will be seen that by mixing the cyanid solution with the oredirectly at the stamp-mill the mixture So it will be observed that willbe necessarily exposed to the air, so that the oxygen in the air will befree to assist in dissolving the gold in solution. However, in thepreferred way of carrying out the invention it is necessary to chargethe mixture within the mixing-tank with air, and to accomplish this thetank is provided, preferably near the top thereof, with an exteriorannular air-blast pipe 41, having a plurality of dependent jet-pipes 42,opening into the tank near the bottom thereof, so as to inject air intothe mixture of ore and solution during the mixing thereof by theagitator.

In connection with the aeration of the ore and cyanid solution the bestresults are accomplished by using hot air. The use of hot air isspecially practical in connection with the jet-pipes of the mixing-tank,and heated air should always be forced into the ore within themixing-tank when the ore is cold or not roasted.

Another feature of importance in carrying out the process is to use thecyanid solution quite warm, and a number of expedients may be resortedto for the purpose of maintaining the solution at a proper temperature.As the ore which is introduced into the tank 1 of the mixing-machine isused while in a Warm condition, the same will necessarily serve to keepthe cyanid solution warm, so that ordinarily in connection with themixing-machine it will not require supplemental means for heating up thecyanid solution; but as it maybe necessary at times to resort tosupplemental means for heating the solution before introducing it intothe mixing-tank one way to accomplish this result is illustrated in thedraw ing, where the solution -supply pipe 40 is shown leading from astorage tank or reservoir 46 for the cyanid solution. This storage tankor reservoir 46 may have arranged therein a heating-coil 47 of piping,the terminals of which coil are connected with any suitable supply forsteam or hot air, whereby a circulation of steam or hot air may bemaintained in the coil, thus insuring the thorough heating up of thecyanid solution before it is delivered through the supply pipe or pipesto the point of use. While the interior heatingcoil within the storagetank or reservoir for the cyanid solution will accomplish the desiredresult, it will be understood that an exterior coil or any extraneousmeans for heating up the solution may be utilized for the same purpose.

In the practical operation of the process it has been found that thebest results are accomplished by heating the air when the same isintroduced through the jet-pipes 42 into the mixture, inasmuch as air ina heated condition has been proven to be very elfect-ive to insure theactiveattacking and dissolving of the gold by the cyanid solution.

It has already been explained that ordinarily a separate heating of thesolution which is used in the mixing-tank is not necessary; but this isalways necessary when the cyanid IIO solution is used at the stamp-millor in any wet crushing-machine instead of water, which operationdispenses with the necessity of introducin g air into the mixture withinthe mixing-tank, as previously explained.

It will of course be understood that when the cyanid solution is used ina warm condition directly at the stamp-mill or'in any wetcrushing-machine said cyanid solution may be heated up in' the storagetank or reservoir in the same manner illustrated in the figure of thedrawing, the essential feature of this particular processresiding inhaving the. solution in a thoroughly-heated condition, yet below thepointof boiling or evaporation.

,While the essential features of the process have already beenindicated, it will be understood that in carrying out the samequicksilver; can be used at any point where free gold is present -such,for instance, as on plates in the stamp-mil] or on any wetcrushing-machine, or alsoon specially-constructed pans or preparedplates within the mixingmachine herein referred toso as to insure thecollecting of all coarse free gold.

Incarrying out the herein-described process in the precipitation of thegoldfrom the cyanid solution any method may be used, such as thezinc-shavings method, electrolysis, or the charcoal method, 85c.

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is-= A method of extracting preciousmetals from their ores, which consists in combining the crushed ore witha cyanid solution while both are in a warm condition, mechanicallymixing the ore and solution by agitation simultaneously with thecommingling thereof, charging the mixture during the agitation with hotair, and finally separating the ore and slush or pulp from the metal insolution, substantially as set forth.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in the presence of two witnesses. t

' JOHN PHILIP SOHUCH, JR.

Witnesses:

F. H. NoLTE, A. B. OLSON.

